Apparatus for controlling refrigerating systems



Jan. 27, 1953 E. F. DICKIESON, JR

APPARATUS FOR CONTROLLING REFRIGERATING SYSTEMS 4 Sheets-Sheet 1 FiledFeb. 4, 1949 INVENTOR. qjyilar/mzb/zzaorz, J;

Jan. 27, 1953 E. F. DICKIESON, JR 2,626,507

APPARATUS FOR CONTROLLING REFRIGERATING SYSTEMS Filed Feb. 4, 1949 4Sheets-Sheet 2 26a AZ} Q gag! 40 R 2?: Y A? Z54 M Ma W E I44 )2! I MatE- a A 7, 1953 E. F. DICKIESON, JR 2,626,507

APPARATUS FOR CONTROLLING REFRIGERATING SYSTEMS Filed Feb. 4, 1949 4Sheets-Sheet; 3

Jam 7, 1953 E. F. DICKIESON, JR 2,

APPARATUS FOR CONTROLLING REFRIGERATING SYSTEMS 4 Sheets-Sheet 4 FiledFeb. 4, 1949 J 40 i @gw W. Z 1 ,M. :1 M

INVENTOR. V lz zz/arJ/jz'c'n zeom j. LL.

TGIF/V579.

Patented Jan. 27, 1953 APPARATUS FOR CONTROLLING REFRIGERATING SYSTEMSEdward F. Dickieson, Jr., Detroit, Mich.; Nathalie L. Dickieson,executrix of said Edward F. Dickieson, J r., deceased, assignor toNathalie L.

Dickieson Application February 4, 1949, Serial No. 74,586

Claims. 1

This invention relates generally to method and apparatus for controllingrefrigerating systems and is an improvement upon my copendingapplication, Serial No. 750,947 filed May 28, 1947, for ControlMechanism.

An object of this invention is to provide a new and improved method ofand apparatus for controlling the operation of refrigerating systems.

Another object of this invention is to provide such a system in whichthecontrolling apparatus is governed at least in part by the temperatureof the refrigerated space.

Another object of this invention is to provide such a refrigeratingsystem in which the operation of the compressor is controlled by meansof the temperature of the enclosed space.

Another object of this invention is to provide in such a system meansfor maintaining the operation of the compressor continuous.

Another object of this invention is to provide a new and improvedcontrol apparatus for use with the refrigerating system.

Other objects of this invention will be apparent from the appendedclaims, the specification and the drawings in which drawings:

Figure 1 is a diagrammatic view of a refrigerating system embodying theinvention and showing the control apparatus in enlarged central verticalsection;

Fig. 2 is a view showing the temperature control dial for use with thecontrol apparatus;

Fig. 3 is substantially a quarter section view showing a modifiedcontrol apparatus for use in the system of Fig. l;

Fig. 4 is a view taken substantially along the line 4-4 of Fig. 3;

Fig. 5 is a view in central vertical section showing a still furthermodified form of control apparatus for use in the system of Fig. 1;

Fig. 6 is a schematic view of a modified form of refrigerating systemsembodying a modified form of the control apparatus;

Fig. 7 is a view in substantially vertical central section of thecontrol elements of Fig. 6;

Fig. 8 is a view in central vertical section of the working cylinderillustrated in Fig. 6 which positions the speed controlling element;

Fig. 9 is a view similar to Fig. 7 but showing a modified form ofcontrol apparatus in which the working cylinder is fabricated integrallywith the control apparatus;

Fig. 10 is a view taken substantially along the line I0-|0 of Fig. 9;

Fig. 11 is a view in quarter section showing a still further modifiedform of the control apparatus for use in the system of Fig. 6; and

Fig. 12 is a view taken substantially along the line l2-I2 of Fig. 11.

Referring to the drawings by characters of reference, like numerals areused to designate like parts in the several views illustrating the samemodification and used with subindices to designate corresponding partsin the several modifications. The numeral [0 indicates generally a spaceto be refrigerated which is provided with an evaporator 8 operativelyconnected with a condensing unit controlled by means of a controlapparatus l8.

Basically the invention contemplates a refrigerating system comprisingthe usual compressor l condenser 2, receiver 4, flow controlling device6, and evaporator 8, all arranged in series circuit in the usual mannerwhereby heat laden low pressure vaporous refrigerant is compressed inthe compressor I and discharged into the condenser 2 where it gives upheat to a surrounding medium, which may be the surrounding air, andcondenses into a liquidwhich flows into the receiver 4. Liquidrefrigerant flows from' the receiver under control of the device 6,which is herein shown to be a thermostatic expansion valve but may be ofother common types, into the evaporator 8 where it vaporizes therebyabstracting heat from the space Ill to be refrigerated. The inventioncontemplates the continuous operation of the compressor l but at a speedwhich is just sufiicient to withdraw enough of the heat ladenrefrigerant vapors to maintain a predetermined desired temperature inthe refrigerated space It]. As will be brought out later thistemperature may be constant or may vary somewhat with change in theamount of heat required to be removed by the evaporator 8.

In the form of the invention shown in Fig. 1, the compressor l ispowered by means of a gasoline engine I 2 through the medium of anendless belt A throttle I6 of the engine [2 controls its speed. Theposition of the throttle IS in turn is controlled by means of a controlapparatus generally designated l8 having a temperature feeler bulb 20located at suitable location in the space It]. As the temperature Withinthe space 10 increases the apparatus [8 acts to open the throttle l6thereby increasing the speed of the engine l2 whereby the compressor Iwill act to withdraw a greater quantity of refrigerant from theevaporator 8 to cause the evaporator to extract more heat from the spacel0 and conversely.

In the system shown in Fig. 6' of this application and in the saidcopending application the associated control apparatus acts in responseto a evaporator pressure whereby this pressure is maintainedsubstantially constant. In many applications this latter type factuation of the control apparatus is sufiicient and has met withpopular approval by the industry, however, in other circumstances betterresults may be had when the control apparatus is responsive totemperature.

The apparatus [8 comprises generally a governing portion 22 and aworking portion 24 which may be integral as shown in Fig. l or thegoverning portion may be separate as shown in Figs. 3 and and associatedwith a separate working portion as shown in Fig. 8. The portion 22comprises a pair of end-to-end arranged hollow housing sections 26 and28 suitably held together. In the form shown in Fig. 1, a housingsection 36 forms an end sectiorrfor the governing portion 22 and alsoforms the housing for the working portion 24, Section 28 is providedwith a cross wall 32 which has a passageway 34 opening centrally andoutwardly of said wall 32 toward the section 26 and which passageway iscommunicatively connected by means ofa small bore conduit 36 with theinterior or" the bulb 20. The wall 32 is provided with a circularshoulder 38 to which is secured'one end of a flexible bellows member 46.The other end of the bellows member 49 is closed by a cap 42 having anoutwardly facing circular shoulder 44. An annular ring 46 seats againstthe shoulder 44 and is held thereto by means of a helical com pressionspring 48. The spring 48 extends toward an end wall 56 of the housingsection 26 and seats against a shoulder on a threaded collar 52 heldagainst rotation by one or more pins 53 slidably received in aperturesin the wall 56. The wall 56 is provided with a bearing aperture 54extending completely therethrough. A threaded adjusting member 56extends completely through the aperture 54 and is provided with aperipheral shoulder 58 which seats against the wall 56. The externalscrew threads-66 mate with complementary internal threads of the collar52 so that when the member 56 is rotated by the calibrated adjustingknob 62 the tension on the spring 48 may be regulated.

The housing section 36 is'provided with a chamber 63 having acylindrical bore portion 64 at its lower end in which is positioned apiston a 66. A piston rod 68 is secured at one end to the piston 66 andextends outwardly of the section 36 through its cover '10. The section36 is also rwided with a side wall 12 which acts as an end wall for thehousing section 28. The wall 12 is provided with an aperture 14extending therethrough and in which is positioned a sleeve 16 forming atits opening into the chamber 63 a valve seat 18. A valve member 86 isslidably received within the member 16 and has a valve head 82 which iscooperable. with the seat 18 to control flow of high pressure actuatingvapor from the receiver 4 through conduit 84 and a passageway 86 in thewall 12 tothe chamber 63 above the piston 66. The portion of the valvemember 86 intermediate the head 82 and a side wall opening in the sleeve16 communicating with the passageway 86 is ofreduced diameter while theendportion thereof away from the head 82 is of 'normaldiameter toslidably fit within the bore of the sleeve 16 for guiding the'member 86.The member 80 extends outwardly of the wall 12 and is threadedly securedto a plate member 88. In order to prevent the escape to atmosphere ofthe fluid which escapes between the sleeve I6 and member 86 a bellows 90is provided. The bellows 96 is preferably concentrically arrangedrelative to the member 80 and is sealed at one end to a dished member 92clamped between the sections 28 and 36 and at its other end to the platemember 88. A plurality of push rods 94 are each secured at one endportion thereof to the plate member 88 and extend outwardly therefromthrough apertures in the wall 32 and are secured at their other endportion to the ring 46.

Referring again to the working portion 24, leakage of fluid toatmosphere between the rod 68 and cover 16 is prevented by a bellows 96concentrically arranged relative to the piston 66 and having one endsealed to the piston 66 and its other end sealed to an annular member 98clamped between the cover 16 and the body portion of the section 36. Thepiston rod 68 is provided with a shoulder I I which engages theunderside of the cover 16 to limit outward movement of the rod 66 andpiston 66 under the influence of spring I62 positioned within the boreportion 64 intermediate the end wall thereof and the piston 66. A portI04 is provided in the piston for permitting a regulated flow of fluidpast the piston and back to the evaporator 8, such flow being througha'passageway I06 and a conduit I63. The passageway I06 not only connectswith the bore portion 64 but also with the space between the dishedmember 92 and end wall 12 whereby this space and the portion of the boreportion 64 beneath the piston 66 will be maintained at the same pressureas that in the evaporator 8. A forcetransmitting means such as the cableH6 connects the rod 68 to the throttle I6 and acts upon inward movementof the piston 66 into the portion 64 to open the throttle I6 which iscontinually urged toward closed position by the spring I I2.

In operation, high pressure refrigerant vapor is discharged from thecompressor I into the condenser 2 wherein it is condensed into a liquidwhich flows to the receiver 4. Liquid from the receiver 4 flows undercontrol of the thermostatic valve 6 to the evaporator 8 whereby the highpressure liquid is reduced in pressure to that of the evaporator 8 afterwhich it evaporates removing heat from the space If]. The heat ladenvapor is removed by the compressor I and discharged into the condenser 2for recirculation in the manner described. The rate at which heat isremoved from the evaporator 8 will be a function of the speed ofoperation of the compressor which speed is controlled by means of theapparatus l8. I

With the position of the parts of the apparatus It as shown, thetemperature within the refrigerated space is above that desired and thepressure of the fluid within the'bulb 26 has increased to increase thepressure inthe chamber surrounded by the bellows 46 so that the end wallor cap 42 thereof has moved outwardly against the force exerted by thespring 48 causing the pins 64 to move the plate member 88 outwardlythereby moving the head portion 82 of the valve 66 into a position toclose off fluid flow through the valve ports I8. With no fluid flowthrough the valve port 78, the pressure across the piston 66 willequalize due to fluid flow through the port In thereby permitting thespring, I02 to move the piston 66 and the piston rod 68 into itsoutermost position with respect to portion 64 and the shoulder I66will'be abutting the cap 10. This permits the spring H2 to move thethrottle I6 to wide open position whereby the gasoline engine I2 will beoperating at full throttle to deliver its maximum power and to drive thecompressor I at its maximum speed. With the compressor I so driven, itwill be obvious that it is removing the maximum quantity of refrigerantvapor from the evaporator 8, thereby removing heat from the space I8 atthe maximum rate.

As the temperature of the space I8 decreases, the temperature of and thepressure within the bulb 28 decreases reducing the pressure in thechamber surrounded by the bellows 48 permitting the spring 48 tocompress the bellows 48, thereby moving the pins 94 and plate member 88to the right as viewed in Fig. 1. This causes the valve member 88 toopen the valve port I8 permitting a predetermined flow of high pressurefluid from the receiver 4 through the conduit 84 and passageway 86 intothe chamber 63 above the piston 86. Since the port I84 is of restrictedflow capacity, the pressure in the chamber 83 will increase causing thepiston 88 to move downwardly and cause the cabl I I8 to move thethrottle I8 toward closed position against the force of the spring H2.The space intermediate the piston 56 and the lower end wall of the boreportion 84 as well as the interior of the bellows member 88 will remainsubstantially at the evaporator pressure since the passageway I88 isconnected through the conduit I88 to the evaporator 8 and has a flowcapacity large enough to carry all of the fluid passed by the passagewayI84. Movement of the throttle I6 toward closed position will decreasethe fuel supplied to the gasoline engine I2 thereby decreasing itsoutput and reducing the speed at which the compressor I is driven. Thisdecreases the amount of heat-laden vapor which is removed from theevaporator 8. As the temperature of the space I8 approaches th desiredtemperature, the temperature of the bulb 28 falls to a predeterminedminimum reducing the pressure within the bellows 48 and permitting thespring 48 to move the valve member 8 to its open position in which thepressure differential maintained across the piston 66 is that requiredto move the piston 88 to its inwardly-most position and the throttle I8toward minimum fuel flow position. The com pressor I will then beoperating at minimum speed and moving a minimum amount of heatladenvapor from the evaporator 8.

Conversely, as the temperature within th space I8 increases, thepressure within the bellows 48 will increase causing the head 42 to movetoward the left against the force of the spring 48 thereby moving thevalve head 82 into a position to reduce fluid flow through the valveport I8. This reduced fluid flow into the chamber 83 decreases thedifierential in pressure across the piston 66 permitting the spring I82to move the piston 66 and the rod 68 upwardly so that the spring II2will move the throttle I6 in an opening direction to increase the outputof the gasoline engine I2 and drive the compressor at a higher speed toremove more heat-laden refrigerant vapor from the evaporator 8.

If it is desired to change the temperature at which the space is to bemaintained, such may be accomplished by rotation of the knob 82, wherebythe force exerted by the spring 48 against the cap 42 may be controlledto determine the pressure within the bellows 48 which is required toposition the valve head 82 relative to the valve port I8. If desired,the control knob 82 may be calibrated as shown in Fig. 2, so thatrotation thereof in accordanc with the calibration will visuallyindicate to the operator the approximate temperature at which the spaceI8 will be maintained.

If the change in pressure in the bulb 28 was the only force actuatingthe valve 88, then the apparatus I8 would operate to provide asubstantially constant temperature within the space I8. Since, however,this force is not the only force, the temperature within the space I8may increase slightly with increasing ambient temperatures. Thisincrease results from the fact that as the ambient temperaturesurrounding the space I8 increases, more heat will leak into the spaceI8 and in order to remove this increased heat an increased difierentialin temperature between the evaporator 8 and the interior of the space I8is necessary. A decrease in evaporator pressure in reflected in acorresponding decrease in pressure in the bellows 98. Such lowering ofthis pressure increases the pressure required to be placed in thebellows 40 to move the valve 88 toward closed position to increase thecompressor speed.

It will now be seen that it is possible by means of varying the relativediameters of the bellows 88 and 98 to proportion the change intemperature within the refrigerated space relative to the change inambient temperature. If it is desired to keep the space I8 at asubstantially constant temperature, then the diameter of the bellowsmember 48 should be made as large as possible with respect to that ofthe bellows member 98. If on the other hand, more change in temperatureof the space is desired with respect to ambient temperature than thediameter of the bellows 98 should be larger with respect to that of thebellows 48.

The control apparatus I8 which is actuated by temperature of the spaceI8 and pressure of the evaporating refrigerant within the evaporator 8for regulating the capacity of the compressor I, also provides means forcontrolling the capacity of the compressor so that as the temperaturewithin the space increases away from the desired or set temperature forany reason the capacity of the compressor to remove heat is increased toprovide what may be called an increasing'recovery factor. Conversely, asthe actual space temperature approaches the desired or set temperaturethe recovery factor may decrease so that the temperature in the space isnot lowered below the desired temperature. The rate of change in therecovery factor is to a large extent determined by the relative areas ofthe bellows 48 and 98, the rate of increase in exerted force of thespring 48 due to a collapsing thereof and the rate of change in fluidflow through the valve port I8 with movement of the valve member 88.Generally it may be assumed that the recovery factor should be high sothat the temperature of the space will be brought to the desiredtemperature as rapidly as possible. In such event slight increases intemperature of the bulb 28 should provide for relatively great changesin fluid flow through the port I8 and the area of the bellows 98 shouldbe small so that any lowering of the evaporator pressure will not tendto close the port 18.

Under other conditions it may be desirable to restrict the magnitude ofthe recovery factor to prevent undue lowering of the evaporatortemperature and pressure and in such event the area of the bellows 98might be increased to provide athrottling movementof the valve member 88relative to the port 18 upon an undesired lowering of the evaporatorpressure. The particular relationships will depend upon the operatingcharacteristics desired for the particular installation.

As the space temperature approaches the desired temperature the engineI2 will be reduced in speed to reduce the capacity of the compressor Iso that it cannot lower the temperature of the space I below thatdesired. It will now be apparent that the invention provides foroperating a refrigerating system with any desired rate of recovery andfurther for operating the system to prevent the temperature of the spacefrom being lowered below the desired temperature.

Referring now to Fig. 3 which shows a modified form of the controlmechanism or apparatus I8a, it will be apparent that this apparatus I8amay be substituted for the governing portion 22 of Fig. 1, and in suchevent, a separate working portion or cylinder 24a such as shown in Fig.8 would be associated therewith for controlling the engine throttle IS.The apparatus I8a distinguishes from the apparatus I8 in that theworking portion 24 of the apparatus I8 has been removed and a casingsection 30a has been substituted therefor. The casing 30a comprisesmeans to close the opposite end of the casing section 25 from thatclosed by the casing section 25a and is provided with an inletpassageway 85a adapted to be connected to receive high pressure vaporfrom the receiver 4 for controlling flow therefrom to the passageway I20which may be connected in fluid flow relation with the portion of thechamber 53a above the piston 56a, Fig. 8. In the modified form shown inFigs. 3 and 4, the poppettype valve 80 has been replaced by asleeve-type valve 80a which is reciprocal within a sleeve 16a carriedWithin the casing section 30a. The sleeve 16a is provided with radialpassageways aligned respectively with the passageway 80a and thepassageway I20. The valve 80a is provided with a circumferential grooveor slot I22 which with the valve 80a in one position aligns itself withthe radial passageways of the sleeve 16a and which is movable outwardlyof this aligned position to restrict and finally to out oif flow offluid from the passageways 86a to the passageway I20. A the valve 80amoves under control of the bellows 400., the flow of high pressure fluidfrom the receiver 4 to the working cylinder 24a is controlledsubstantially in the same manner as the fluid flow was controlled by theapparatus I8 upon movement of the valve member 80. In order to permitthe escape of the gaseous fluid which may pass downwardly between thevalve member 80a and the sleeve 16a, the section 30a is provided with abranch passageway I24 (Fig. 3) which communicates with the passageway Iaconnected to the evaporator by means of conduit I08a. The passageway I20is arranged to be communicatively connected to an inlet port I25 of theworking cylinder 24a.

It will be obvious from the description of the portion 24a that as theflow of fluid passed by the valve member 80a increases, the pressure inthe chamber 63a above the piston 65a will increase causing the piston65a to move downward whereby its piston rod 63a will move downwardly tocause the throttle I0 to move toward closed position. The space belowthe piston 56a is connected to the low pressure side of therefrigerating system by means of a conduit attached to the outlet I 28thereof for discharge of the fluid passed by the passageway or port I04a. It will be obvious with the form of control shown in Figs. 3 and 4,when associated with the working portion, shown in Fig. 8, that it willbe possible to locate the control apparatus IBa closely adjacent thespace to be refrigerated and the working portion 24a closely adjacentthe throttle of the engine of which it is associated substantially asshown in Fig. 6. Under some installation conditions in which there isquite a distance between the refrigerated space and the condensing unit,this type of apparatus may have certain advantages over the form shownin Fig. 1.

In Fig. 5, there is shown a still further modified form of apparatus IBbwhich may be used in place of the apparatus I8a and which compriseshousing sections I50 and I52 between which there is clamped a platemember I54. The housing section I52 contains the valve member b havingthe head 82b for controlling the flow of high pressure vapor from theinlet passageway 86b to the outlet passageway I20b. The valve member 80bis concentrically positioned within a sleeve 15b and has its upper endthreadedly secured to a cap member I55. The platelike member I54 has acentral aperture therethrough through which the valve member 801;extends. A bellows 90b is arranged concentric to the valve member 80band is sealed at its lower end to the platelike member I54 and at itsupper end to the cap member I55. A passageway 341) within the plate I 54opens upwardly therefrom exterior to the bellows 90b and within a secondbellows 40b which is also arranged concentrically with the bellows 90b.The bellows 90b is sealed at its lower end to the plate member I54outwardly of the opening of the passageway 341) and sealed at its upperend to the cap member I56. The apparatus I8b shown in Fig. 5 operatessubstantially like the apparatus I8a as already described and isarranged to have the passageway 86b connected to the receiver 4 by aconduit (not shown), the passageway I05a connected to the evaporator,and the passageway I20b connected to the passageway I26 of the cylinder24a.

In Fig. 6 there is shown a refrigerating system having a gasoline engineI2, a compressor I, a space I0 to be refrigerated, an evaporator 8within the space, a thermostatic expansion valve 0, a condenser 2 and areceiver 4, all operatively connected together in the usual manner bymeans of conduits or other fluid conveying means. In this system, theapparatus I8c is not provided with a temperature bulb similar to thebulb 20 but is actuated by the evaporator pressure communicated theretoby the conduit 200. High pressure fluid for actuation of the cylinder24a, Fig. 6, is communicated to the apparatus I80 by the conduit I08 anda conduit I2I conveys the fluid from the apparatus I8c to the cylinder24a. The controlling apparatus I 80 is more clearly shown in Fig. 7. Theoperation of the system in Fig. 6 is substantially the same as that ofthe system shown in my said copending application, but the particularform of controlling apparatus as shown in Figs. '7 and 8, is believed tobe an improvement over the form of apparatus shown in my said copendingapplication. In this form of apparatus, the pressure in the evaporatoris communicated to the interior of the bellows 900 by means of a conduit200 open at one end to the evaporator 0 and at the other end to apassageway 202 of the apparatus I Be. The upper end of the bellows isclosed by means of a cap member I 560, the upward movement of which 9 isopposed by means of a compression spring 480. The force exerted by thespring 480 may becontrolled by means of the knob 62c similarly as wasthe force exerted by the spring 48. High pressure fluid fromthe receiver6 is communicated by means of a conduit I98 to the inlet passageway 204of the apparatus I80 and its flow outwardly through the outlet 206 ofthe apparatus I80 is controlled by means of the position of the valve800 with respect to the valve port 180. The outlet 206 is connected bymeans of a conduit, or other fluid conveying means to the inlet I26 ofthe working portion of cylinder 24a for control of the throttle.

Figs. 9 and illustrate a still further modi-= fled form of the controlapparatus for use in the system of Fig. 6 which is quite similar to theapparatus l8 used in connection with the system of Fig. l insofar as theworking portion 24d is formed integrally with the controlling apparatusI 8d. The apparatus of Fig. 9 is similar to the apparatus of Fig. '7, inthat there is no provision therein for the application of pressurecommunicated thereto as by the bulb 26 of the system of Fig. 1. It willbe noted from a study of Fig. 10 that the working portion 2401 issubstantially identical with the working portion 24a shown in Fig. 8,except that it is directly connected with the control apparatus, wherebythe same may be used as a single unit.

The modification shown in Figs. 11 and 12 of the apparatus [8 issubstantially the same as the apparatus lild shown in Fig. '7, exceptthat instead of the poppet-type valve a sleeve-type valve similar tothat shown in connection with the modification shown in Fig. 3 isprovided. In the modification shown in Fig. 11, the means for attachingthe apparatus I81), I80, or 18d to a supporting member 300 is shown. Itwill be apparent that the casing sections 261). 260, or 26d are providedwith external threads 302 upon which may be threaded a nut 304. Theapparatus is inserted through an aperture 306 in the supporting member300 after which an annular ring 308 is slid over the upper end of thecasing sections 26b, 260, or 26d and is held against outward movement bymeans of a snap ring 3H1. The nut 304 is then screw threaded along thethreads 302 whereby the nut clamps the annular ring 308 to the support300. The control knob He may then be inserted in place and held theretoby means of the spring detent 3 l2.

This application is directed toward an improvement over the inventionshown and claimed in my said copending application in that thisapplication contains claims directed toward an improved controlmechanism and also claims directed toward an improved controlling systemfor maintaining the temperature in a refrigerated space withinpredetermined limits by means of a constantly operating condenser unit.

What is claimed and what is desired to be socured by United StatesLetters Patent is as follows:

1. An apparatus for controlling a refrigerating system having a lowpressure portion and a high pressure portion comprising a casing, apressure sensitive element within said casing having a por tion movableas a function of the pressure on said element, means responsive totemperature of a space to be refrigerated for controlling the pressureon said element, means providing a fluid flow passageway adapted to beconnected between said system portions, a pressure sensitive actuatorsensitive to the pressure in said passageway,

controlling'means operatively connected to said actuator for actuatingthereby as a function of the pressure applied to said actuator, valvemeans controlling flow of fluid through said passageway for controllingthe fluid pressure in said actuator, and means operatively connectingsaid element portion and said valve means whereby said valve means isoperable to control the fluid pressure in said actuator as a function ofthe temperature of the space and independently of the pressure in saidlow pressure portion.

2. An apparatus for controllinga refrigerating system having a lowpressure portion and a high pressure portion comprising a casing, asealed fluid pressure system separate from said refrigerating system andresponsive to temperature of a space to be refrigerated and including apressure sensitive element within said casing, means providing a fluidflow passageway adapted to be connected between said refrigeratingsystem portions, a pressure sensitive actuator sensitive to the pressurein said passageway, controlling means operatively connected to saidactuator for actuating thereby as a function of the pressure applied tosaid actuator, valve means controlling flow of fi-uid through saidpassageway for controlling the fluid pressure in said actuator, andmeans operatively connecting said element portion and said valve meanswhereby said valve means is operable to control the fluid pressure insaid actu ator as a function of the temperature of the space.

3. An apparatus for controlling a refrigerating system having a lowpressure portion and a high pressure portion comprising a casing havinga wall with an aperture therethrough and a pressure chamber, a valvecontrolling flow through said aperture, a sealed fluid pressure systemersponsive to the temperature of a space to be cooled and having apressure sensitive element within said casing, means operativelyconnecting said element and said valve, means including said apertureand said chamber and providing a fluid flow passageway adapted to beconnected between said system portions, a movable pressure sensitivewall for said chamber and movable in response to pressure in saidchamber, and controlling means operatively connected to said movablewall whereby said controlling means is actuated as a function of thepressure acting on said movable wall.

4. The combination of claim 3 in which said pressure sensitive walllimits flow through said passageway providing means and is provided witha restricted fluid flow orifice to permit a limited flow of fluid pastsaid pressure sensitive wall.

5. An apparatus for controlling a refrigerating system having a lowpressure portion and a high pressure portion comprising, a casing havinga pair of casing chambers separated by a dividing wall, said wall beingprovided with a first passageway extending therethrough and openingoutwardly at opposite sides of said wall into said chambers, said wallhavinga second passageway communicating with and extending laterally ofsaid first passageway intermediate its ends, a valve cooperable with afirst portion of said first passageway which opens outwardly of saidwall into one of said chambers for controlling fluid flow through saidsecond passageway, said valve having a stem extending through a secondportion of said first passageway which opens outwardly of said wall intoa second of said chambers, a sealed fluid pressure system responsive tothe temperature of a space to be cooled and hav- 11 ing a pressuresensitive element in said second chamber, a fluid seal within saidsecond chamher and sealing said first passageway against flow of fluidinto said second chamber, means including said seal for operativelyconnecting said valve and said element, fluid conveying means includingsaid first and second passageways and said first chamber for providing afluid flow passageway adapted to be connected between said systemportions, and a movable pressure sensitive wall for said first chamberand movable in response to pressure within said chamber.

EDWARD F. DICKIESON, JR.

REFERENCES CITED The following references are of record in the flle ofthis patent:

Number UNITED STATES PATENTS Name Date Williams et a1 Jan. 21, 1913Jones Nov. 14, 1933 Thomas July 24, 1934 Wile Sept. 24, 1940 Euwer Sept.30, 1941 Henny June 1, 1943 Newton Jan. 16, 1945 Atchison Apr. 27, 1948-Winchester Sept. 14, 1948 Newton Nov. 16, 1948 Lathrop Feb. 14, 1950Lange June 6, 1950

